package collection;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class ListDemo {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("one");
        list.add("two");
        list.add("three");
        list.add("four");
        list.add("five");
        list.add("one");
        System.out.println("list:"+list); //[one,two,three,four,five]


        //E get(int index):获取指定下标所应对的元素
        String e = list.get(2);
        System.out.println(e); //three

        for(int i=0;i<list.size();i++){
        System.out.println(list.get(i));}


        Iterator<String> it = list.iterator();
        while(it.hasNext()){
        System.out.println(it.next());}

        for(String s: list){
         System.out.println(s);}

         System.out.println("------");

         //E set(int index, E e):
         //list.set(2,"six");
        String old = list.set(2,"six");//将list中的下标为2的元素设置为six,将源数据返回old
        System.out.println("list:"+list);
        System.out.println(old);  //three

        //E remove(int index):删除指定位置元素，并返回指定位置元素
        //list.remove(2); //删除下标为2的元素，并将被删除元素返回s
        String s = list.remove(2);
        System.out.println("list:"+list);
        System.out.println(s);

        /*
        void add(int index,E e):
        将给定元素e添加到index所指定的位置，相当于插入操作
         */
         list.add(3,"seven"); //在list下标为3的位置插入seven
        System.out.println(list);
    }
}
